Has Teriparatide changed your fingernails?

@gently As teriparatide helpes making new matrixes of collagen in the bones (that hopefully get mineralized later on by calcium), perhaps it could help form collagen as building blocks for the nails too?

This is just wild speculation of me...

WilWeten, now that you made me think about it, fingernails aren't calcium, but keratin. I vaguely remember something about pth and pthrp decreasing the number of keratin cells while forcing the fewer to mature more fully. Either I remember or misremember.

I’m on my fifth month of Forteo and my nails have definitely improved! They were thin and peeling as well and now I have length and they are getting stronger.

@gently I just asked CLAUDE AI and got this interesting answer:

Possible (theoretical) connections to nails

IGF-1 stimulation: Both drugs increase circulating and local IGF-1, a growth factor that also supports keratinocyte proliferation and epidermal/nail matrix turnover. In theory, more IGF-1 signaling could support faster or more robust nail plate formation.
Calcium/phosphate handling: PTH analogs affect calcium and phosphate metabolism. Nail brittleness is sometimes (loosely) linked to mineral status, though the actual evidence tying calcium levels to nail splitting is weak.
Systemic anabolic effect: Because these drugs shift the body toward a more "build tissue" state (increased collagen synthesis, connective tissue turnover), there's a hand-wavy argument that connective tissue elsewhere, including the nail bed and matrix, could benefit.

The caveat
None of this is established clinically. There are no trials or approved indications showing teriparatide or abaloparatide improve nail splitting (onychoschizia), and they're not prescribed for that reason — the injection cost, side-effect profile (hypercalcemia, orthostatic hypotension, osteosarcoma risk in rodent studies), and administration burden make them wildly disproportionate to a cosmetic nail concern even if a small effect existed.

If splitting nails is the actual issue you're trying to solve, the usual culprits are frequent water/detergent exposure, low humidity, iron deficiency, thyroid dysfunction, or (rarely) biotin deficiency — worth checking those before anything more exotic.

I am in the second month of Forteo/teriparatide. I noticed that my nails are peeling less and are a bit stronger than before this treatment, too. However, I have side effects such as severe knee pain and uncomfortable jaw joint pain that fluctuate during the day.

Through my 2 years on Forteo may fingernails had never been stronger. It was very noticeable to me - no breaking, splitting.

Now that I’m off Forteo my nails are ok but not as robust as they were.